Structural Systems Used in Facility Construction

Structural systems form the load-bearing skeleton of every facility, determining how forces move through a building from roof to foundation and into the ground. The selection, design, and construction of these systems are governed by model building codes, material-specific standards, and permitting workflows that vary by occupancy class and jurisdiction. This page covers the principal structural system types used in US facility construction, the regulatory and code framework that classifies them, and the decision boundaries that govern system selection across project types.

Definition and scope

A structural system in facility construction is the integrated assembly of members — columns, beams, walls, slabs, and foundations — that resists gravity loads, lateral forces (wind and seismic), and dynamic loads, transferring them to the ground in a controlled and code-compliant manner. The International Building Code (IBC), published by the International Code Council (ICC) and adopted in some form by all 50 states, classifies buildings by occupancy group and construction type, with construction type directly governing which structural materials and assemblies are permitted.

The IBC establishes five primary construction types (Type I through Type V), each subdivided into A and B categories based on fire-resistance ratings. Type I construction, the most restrictive, requires noncombustible structural framing with the highest fire-resistance ratings and is associated with high-rise and institutional occupancies. Type V, the least restrictive, permits combustible wood-frame construction and is most common in low-rise residential and light commercial work. Structural system selection is therefore not purely an engineering decision — it is constrained upstream by code-mandated construction type for the occupancy and height in question.

Structural engineering practice in the US is further governed by material-specific standards produced by organizations including the American Institute of Steel Construction (AISC), the American Concrete Institute (ACI), the American Forest & Paper Association (AF&PA) through its National Design Specification (NDS) for wood, and the Masonry Standards Joint Committee (MSJC) for masonry systems. Each standard defines allowable stresses, connection requirements, and detailing criteria that inform permit-ready construction documents.

How it works

Structural systems function by creating continuous load paths from the point of load application — typically roof, floors, and exterior walls — down through the primary framing, to lateral force-resisting elements, and finally into the foundation and soil. The system must address two distinct load categories:

1. Gravity loads — dead loads (self-weight of structure, finishes, and fixed equipment) and live loads (occupants, furniture, and movable equipment), with live load minimums set by ASCE 7, Minimum Design Loads and Associated Criteria for Buildings and Other Structures, published by the American Society of Civil Engineers.
2. Lateral loads — wind pressure and seismic forces, also governed by ASCE 7, which maps the US into wind speed zones and seismic design categories (SDC A through F), with SDC determining the stringency of ductile detailing requirements.

The primary structural framing carries gravity loads through beams and columns or load-bearing walls to the foundation. The lateral force-resisting system (LFRS) is a distinct subsystem that can take the form of moment frames, braced frames, shear walls, or diaphragm-collector assemblies. In complex facilities, the LFRS is engineered independently from the gravity system, though both must be compatible and coordinated through the structural drawings that accompany permit submissions.

Foundation systems translate all superstructure loads into the ground. Shallow foundations (spread footings, mat slabs) are used where bearing capacity is adequate within a few feet of grade. Deep foundations — driven piles, drilled piers, or helical piles — are required when shallow soils cannot support design loads, a determination made through geotechnical investigation reports that most jurisdictions require as part of the permit package. Structural design decisions inform broader facility listings categories, as foundation type, framing material, and lateral system all affect project classification and contractor specialization.

Common scenarios

Structural system selection follows recognizable patterns by facility type and scale:

• Steel moment frame or braced frame — dominant in mid-rise to high-rise office buildings, hospitals, and industrial facilities where open floor plans require long spans and seismic or wind demands are elevated. AISC 341 governs seismic design of steel frames in moderate and high SDCs.
• Cast-in-place concrete shear wall and flat-plate — common in multi-story residential, hotel, and parking structures where repetitive floor plates, fire resistance, and vibration control justify the forming costs. ACI 318 is the governing standard for reinforced concrete.
• Precast concrete — used in parking structures, warehouses, and tilt-up industrial buildings. Precast components are fabricated off-site and erected on-site, with connections designed to the Precast/Prestressed Concrete Institute (PCI) design manual criteria.
• Light wood frame (platform or balloon) — prevalent in low-rise facilities, clinics, and mixed-use podium buildings up to four or five stories of wood over a concrete podium base. NDS governs member sizing; IBC limits combustible construction height.
• Load-bearing masonry — found in smaller institutional buildings, schools, and renovations of existing masonry stock, with structural performance governed by TMS 402/602.

Permitting for each scenario requires stamped structural drawings from a licensed structural engineer of record (SER), geotechnical data, and in seismically active jurisdictions, a seismic hazard analysis. Third-party structural plan review is required in jurisdictions operating under IBC Section 1703 for certain occupancy classes. Details on how these project types are classified and navigated can be found through the facility directory purpose and scope reference.

Decision boundaries

System selection converges on four intersecting constraints:

1. Code-mandated construction type — IBC Table 601 sets fire-resistance ratings by construction type. A hospital occupancy (Group I-2) in most jurisdictions requires Type I or Type II construction, eliminating wood-frame options regardless of cost.
2. Seismic design category — In SDC D, E, or F — covering much of the western US, the New Madrid zone, and coastal regions — ASCE 7 and AISC 341/ACI 318 impose special ductile detailing that increases cost and schedule relative to ordinary or intermediate framing systems.
3. Span and layout requirements — Long-span requirements (warehouse clear spans exceeding 60 feet, or column-free hospital operating suites) preclude load-bearing masonry and light wood frame and point toward steel or prestressed concrete.
4. Schedule and procurement — Steel and precast concrete involve fabrication lead times of 12 to 20 weeks on typical projects, affecting construction start dates. Cast-in-place concrete is more schedule-flexible but weather-sensitive and labor-intensive.

The contrast between steel moment frame and concrete shear wall systems illustrates a recurring decision boundary: moment frames offer architectural flexibility and faster erection but carry higher steel costs in seismic zones requiring special moment frames (SMF); shear walls offer stiffness and inherent fire resistance but constrain floor plan flexibility and require more complex forming. Structural engineers of record, working within the design team's project delivery model, resolve these tradeoffs through preliminary system studies submitted before design development documents are issued to the permitting authority. How these roles are structured across project delivery is described further in the how to use this facility resource reference section.

References

• International Building Code (IBC) — International Code Council (ICC)
• ASCE 7, Minimum Design Loads and Associated Criteria for Buildings and Other Structures — American Society of Civil Engineers
• American Institute of Steel Construction (AISC) — AISC 341 Seismic Provisions
• American Concrete Institute (ACI) — ACI 318, Building Code Requirements for Structural Concrete
• American Wood Council (AWC) — National Design Specification (NDS) for Wood Construction
• Precast/Prestressed Concrete Institute (PCI) — PCI Design Handbook
• The Masonry Society — TMS 402/602 Building Code Requirements and Specification for Masonry Structures